John F. Kelly

Born in Boston, Massachusetts, Kelly enlisted in the Marine Corps during the Vietnam War and was commissioned as an officer near the end of college. He rose through the ranks, eventually serving in his last military post from 2012 to 2016 as a four-star general leading United States Southern Command, the unified combatant command responsible for American military operations in Central America, South America, and the Caribbean.
Before joining the Trump administration in January 2017, Kelly had been on the board of advisors of DC Capital Partners, an investment firm that owns Caliburn International. Kelly was selected as the Trump administration's first Secretary of Homeland Security. Kelly earned a reputation for being an aggressive enforcer of immigration law. After six months, he was selected to replace Reince Priebus as White House chief of staff in an attempt to bring more stability to the White House. He was the first career military officer to serve in the position since Alexander Haig during the Nixon and Ford administrations. Provided by Wikipedia